The 3-D imaging technology disclosed in Stettner et al, U.S. Pat. Nos. 5,446,529, 6,133,989 and 6,414,746 provides with a single pulse of light, typically pulsed laser light, all the information of a conventional 2-D picture along with the third dimensional coordinates; it furnishes the 3-D coordinates of everything in its field of view. This use is typically referred to as flash 3-D imaging in analogy with ordinary digital 2-D cameras using flash attachments for a self contained source of light. As with ordinary 2-D digital cameras, the light is focused by a lens on the focal plane of the LADAR sensor, which contains an array of pixels called a focal plane array (FPA). In the case of a LADAR sensor these pixels are “smart” and can collect data which enables a processor to calculate the round-trip time of flight of the laser pulse to reflective features on the object of interest. Each smart pixel also collects data associated with the returning laser pulse shape and magnitude. The work of Stern and Cole, “High-sensitivity, wide-dynamic-range avalanche photodiode pixel design for large-scale imaging arrays”, appearing in the Journal of Electronic Imaging 19(2), 021102 (April-June 2010), is referenced for design features and fabrication techniques which may improve the efficiency and isolation of the elements of the focal plane detector arrays common to the several designs described herein.
One value of these flash LADAR sensors, as opposed to competing designs in which one or more pixels is scanned over the field of view, is the elimination of the precision mechanical scanner, which is costly, high maintenance and typically large and heavy. The pixels in the focal plane of a flash LADAR sensor are automatically registered due to their permanent positions within the array. Further, by capturing a frame of data as opposed to one or a few pixels with one laser pulse, the data rate is greatly increased while weight and volume are reduced. Because each frame of data is captured from the reflection of a short duration laser pulse, moving objects or surfaces of stationary objects may be captured from a moving platform without blurring or distortion.
It is therefore desirable to provide a device to generate 3D data which is both low cost and flexible in manufacture due in part to the modular nature of the design. It is also an object of the invention to provide a modular ladar sensor unit as a component which may be utilized ubiquitously in any application by any imaging platform, computer, or host device provided with a number of basic electrical and mechanical interfaces. It is a further object of the invention to provide a flash ladar sensor component to a 3-D video production system which is both flexible and rapidly reconfigurable, allowing it to be adapted to any field of play, theater, arena or surveillance sector.